For tires used in vehicles such as, for example, automobiles, it is required to obtain inherent information of each tire immediately to control management of tires such as manufacturing, shipment, distribution, and maintenance etc. Such inherent information includes types, production numbers, specifications, properties, production histories, use histories, and/or the like.
According to the production liability low (PL law) particularly, in a case where a defected article leads to damage on a human body or infringement of property, manufactures have a responsibility of compensating the loss caused by the defected article, regardless whether or not the damage is caused by their fault. Thus, it is indispensable for manufactures to manage their tires individually.
Further, U.S. department of transportation (DOT) obliges the manufactures to identify, as information for warranty of each tire, a production number and a vehicle identification number (VIN) so as to enable identification and management of a tire individually.
Method for adding such inherent information to a tire have been proposed. One such conventional method is to attach a sticker of a bar code system to a surface or inner surface of a tire (see Japanese Unexamined Patent Publication 266811/1995 (Tokukaihei 7-266811)). The other conventional method is to mark an identification code on a surface of a tire (see Japanese Unexamined Patent Publication 084681/2000 (Tokukai 2000-084681)).
The methods using the bar code system or marking, however, suffer from problems that the amount of information is limited due to a display area, and that the information attached or marked cannot be identified since it fades away through exfoliation, abrasion, and/or the like. Particularly, in the bar code system, the surface of a tire is contaminated under extreme use environment, so that the information cannot be read out. To address the problem, there has been a measure that a bar code sticker is attached inside a tire. In this case, however, information attached in the bar code sticker cannot be used after the tire is mounted to a vehicle.
To solve the problems of the conventional methods, consideration is made to a method which uses a non-contact IC tag (hereinafter referred to as RFID tag). An RFID tag can store large amount of information in an IC. Further, an RFID tag can be externally read out with a distance of several centimeters to several meters. This enables information stored in a tag to be easily read out even when the tag is attached inside a tire.
However, a process for manufacturing a tire includes steps such as a vulcanization step during which a tire is required to be under high temperature and pressure loads.
Further, a tire may be bended and/or stretched to be deformed when it is used, or a tire may have a high temperature by being in friction with a load surface or by other factors. Such a situation may cause an RFID tag (i) to be under extreme environment such as a high temperature and a high pressure when the IC tag is attached inside a tire, or (ii) to be deformed by being bended and stretched repeatedly when a tire is used. This gives rise to a problem of breaking an IC or a coil which constitutes an RFID tag, or breaking bonding points at which the components are connected to each other.
To prevent such breakage of an RFID tag, a common method has been proposed in which an RIFD tag is bonded to an inner surface of a tire (see Japanese Unexamined Patent Publication 013449/2004 (Tokukai 2004-013449)).
Similarly, to prevent the breakage of an RFID tag, another method has been proposed. In the method, as shown in a side cross sectional view of FIG. 14(a), an IC section 123 of a non-contact IC tag 124 is sealed with a resin such as epoxy 121. Further, the method employs wires 122 which are made of copper having a thickness of about φ0.1 mm, and which are relatively stiff to bending of a coil.
However, the above methods suffer from the following problem. As shown in FIG. 14(b), if a bonding layer 126 or the like is tightly attached to a tire 127, i.e., an elastic rubber member, the flexibility of the non-contact IC tag 124 is interfered. This causes cracking inside a tire due to a difference in deformation capability between the non-contact IC tag 124 and the tire 127, resulting in degrading the safety of the tire.
Further, the above methods suffer from the problems of (i) breaking the hard epoxy 121 because the elastic deformation capability of the epoxy 121 cannot follow that of the tire 127, causing breakage of the internal IC section 123 rather easily, and (ii) increasing the number of steps for manufacturing a non-contact IC tag, resulting in a cost increase of the non-contact IC tag.